GB1039531A - Thrust compensator for a group of jet lift engines for an aircraft - Google Patents

Abstract

1,039,531. Jet propulsion plant. ELLIOT BROS (LONDON) LTD. Jan. 1, 1964 [Jan. 4, 1963], No. 533/63. Heading F1J. [Also in Division B7] In an arrangement for maintaining a predetermined total lift thrust for an aircraft, each engine of a group of three jet lift engines arranged in a wing pod has means, such as a pitot tube, a static tapping or a pair of venturis, in the jet pipe for forming a pressure source representative of the pressure therein. Each pressure source is connected with a double-acting cylinder 75, 76 or 77 through a pair of conduits and a valve 88, 89 or 90, which valve, in the event of fracture of one of conduits, seals the fractured conduit. A common chamber. 79 having a controlled leak device 103 is connected to the piston rod end of each cylinder 75, 76, 77 through conduits 97, 99, 101 and non-return valves 98, 100, 102, and with the other end of each cylinder through conduits 113, 114, 115. Due to the non-return valves, the fluid in the chamber 79 assumes the pressure of the highest representative pressure. One or more cylinders 78 connected, through a valve 91 and a pair of conduits, with a representative pressure source of one or more lift-forward thrust engines may be provided. The four piston rods 106 to 109 are fixed to a member 110 carrying a throttle control rod 112 connected to each of the three lift engines and the pilot's primary throttle control. During normal operation the pressure differential across the four pistons in the cylinders 75 to 78 is balanced by the action of a spring 111 so that the pistons assume the positions shown. However, in the event of reduced power of one of the engines, the pistons and the rod 112 move to the right resulting in opening of the throttles of the three lift engines and production of makeup thrust. The diameter of the cylinder 78 is less than that of each of the cylinders 75, 76, 77 so that failure of the lift-forward thrust engine produces a smaller make-up thrust than that caused by failure of one of the main lift engines. In an alternative embodiment, Fig. 1 (not shown), the four cylinders and the common chamber are formed in a single housing with the ends of the cylinders opening into the chamber. Further, a single conduit connects each representative pressure source with the respective cylinder, and has a branch which connects with the common chamber. In modifications of these embodiments the balancing spring may be replaced by a pneumatic system or a mechanism equivalent to a zero rate spring, or a balancing spring may be associated with each cylinder, the piston rods being interconnected through a series of pivoted linkages arranged to move the throttle control rod an amount representative of the algebraic sum of the individual movements of the piston rods.